Continuous production of n-butylacrylate free from dibutylether

Abstract

N-Butylacrylate is produced by reacting acrylic acid with n-butanol in liquid phase in contact with an acid cation exchanger as a catalyst. To this end, the acrylic acid and butanol are reacted in a molar ratio from 1:1 to 1:2.5, at 80° to 130° C, under a pressure from 3 to 15 atmospheres gauge, and for 20 - 90 minutes.

We claim: 
     
       1. In the process for making n-butylacrylate by reacting acrylic acid with n-butanol in liquid phase in contact with an acid cation exchanger as a catalyst, the improvement, which comprises continuously introducing into, and reacting in, a reaction zone acrylic acid and n-butanol in a molar ratio within the range 1:1 and 1:2.5, at temperatures within the range 80 and 130° C, under a pressure within the range 3 and 15 atmospheres gauge, and for reaction periods within the range 20 and 90 minutes, the reaction zone being filled with an acid cation exchanger; delivering the resulting esterification mixture to a first distillation zone, distilling off near the head of the first distillation zone a ternary mixture consisting of butylacrylate, butanol and water, condensing the mixture and separating it into an organic phase and an aqueous phase, recycling the bulk of the aqueous phase to the head of the first distillation zone and removing the aqueous phase balance portion; removing concentrated acrylic acid from the bottom portion of the first distillation zone, distilling off higher boiling fractions and recycling the acrylic acid to the reaction zone; delivering the organic phase recovered from distillate of the first distillation zone to a second distillation zone, distilling off near the head of the second distillation zone a ternary mixture consisting of butylacrylate, butanol and water, condensing the mixture and separating it into an organic phase and an aqueous phase, recycling the organic phase to the head of the second distillation zone and removing the aqueous phase; delivering base product obtained in the second distillation zone and consisting of butylacrylate and butanol to a third distillation zone, distilling off near the head of the third distillation zone a butanol/butylacrylate-azeotrope, condensing the azeotrope and recycling it to the reaction zone, and removing pure n-butylacrylate through the bottom portion of the third distillation zone.